CentOS 7.6安装Kubernetes v1.15.1
kubeadm是Kubernetes官方提供的用于快速安装Kubernetes集群的工具，伴随Kubernetes每个版本的发布都会同步更新，kubeadm会对集群配置方面的一些实践做调整，通过实验kubeadm可以学习到Kubernetes官方在集群配置上一些新的最佳实践。
最近发布的Kubernetes 1.15中，kubeadm对HA集群的配置已经达到beta可用，说明kubeadm距离生产环境中可用的距离越来越近了。
Kubernetes集群组件:
- etcd 一个高可用的K/V键值对存储和服务发现系统
- flannel 实现夸主机的容器网络的通信
- kube-apiserver 提供kubernetes集群的API调用
- kube-controller-manager 确保集群服务
- kube-scheduler 调度容器，分配到Node
- kubelet 在Node节点上按照配置文件中定义的容器规格启动容器
- kube-proxy 提供网络代理服务
一、环境介绍
| 主机名 | IP地址 |
| k8s-master | 192.168.169.21 |
| k8s-node1 | 192.168.169.24 |
| k8s-node2 | 192.168.169.25 |
| k8s-node3 | 192.168.169.26 |
1、操作系统： CensOS7.6
[root@k8s-master ~]# cat /etc/RedHat-release
CentOS Linux release 7.6.1810 (Core)
2、Kubernetes版本 v1.15.0
kube-apiserver v1.15.0
kube-controller-manager v1.15.0
kube-proxy v1.15.0
kube-scheduler v1.15.0
etcd 3.3.10
pause 3.1
coredns 1.3.1
二、准备
2.1系统配置
在安装之前，需要先做如下准备。4台CentOS 7.6主机如下：
升级系统
# yum -y update
配置Host
# cat /etc/hosts
127.0.0.1 localhost
192.168.1.21 k8s-master
192.168.1.24 k8s-node1
192.168.1.25 k8s-node2
192.168.1.26 k8s-node3
如果各个主机启用了防火墙，需要开放Kubernetes各个组件所需要的端口，可以查看Installing kubeadm中的”Check required ports”一节。 这里简单起见在各节点禁用防火墙：
# systemctl stop firewalld
# systemctl disable firewalld
禁用SELINUX：
# setenforce 0
# sed -i 's/SELINUX=enforcing/SELINUX=disabled/g' /etc/selinux/config
#
SELINUX=disabled
创建/etc/sysctl.d/k8s.conf文件，添加如下内容：
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
net.ipv4.ip_forward = 1
执行命令使修改生效。
# modprobe br_netfilter
# sysctl -p /etc/sysctl.d/k8s.conf
2.2kube-proxy开启ipvs的前置条件
由于ipvs已经加入到了内核的主干，所以为kube-proxy开启ipvs的前提需要加载以下的内核模块：
ip_vs
ip_vs_rr
ip_vs_wrr
ip_vs_sh
nf_conntrack_ipv4
在所有的Kubernetes节点上执行以下脚本:
# cat > /etc/sysconfig/modules/ipvs.modules <<EOF
#!/bin/bash
modprobe -- ip_vs
modprobe -- ip_vs_rr
modprobe -- ip_vs_wrr
modprobe -- ip_vs_sh
modprobe -- nf_conntrack_ipv4
EOF
# chmod 755 /etc/sysconfig/modules/ipvs.modules && bash /etc/sysconfig/modules/ipvs.modules && lsmod | grep -e ip_vs -e nf_conntrack_ipv4
上面脚本创建了的/etc/sysconfig/modules/ipvs.modules文件，保证在节点重启后能自动加载所需模块。 使用lsmod | grep -e ip_vs -e nf_conntrack_ipv4命令查看是否已经正确加载所需的内核模块。
接下来还需要确保各个节点上已经安装了ipset软件包
# yum -y install ipset
为了便于查看ipvs的代理规则，最好安装一下管理工具ipvsadm
# yum -y install ipvsadm
如果以上前提条件如果不满足，则即使kube-proxy的配置开启了ipvs模式，也会退回到iptables模式
2.3安装Docker
Kubernetes从1.6开始使用CRI(Container Runtime Interface)容器运行时接口。默认的容器运行时仍然是Docker，使用的是kubelet中内置dockershim CRI实现。
安装docker的yum源:
# yum install -y yum-utils device-mapper-persistent-data lvm2
# yum-config-manager \
--add-repo \
https://download.docker.com/linux/centos/docker-ce.repo
查看最新的Docker版本：
# yum list docker-ce.x86_64 --showduplicates |sort -r
docker-ce.x86_64 3:18.09.7-3.el7 docker-ce-stable
docker-ce.x86_64 3:18.09.6-3.el7 docker-ce-stable
docker-ce.x86_64 3:18.09.5-3.el7 docker-ce-stable
docker-ce.x86_64 3:18.09.4-3.el7 docker-ce-stable
docker-ce.x86_64 3:18.09.3-3.el7 docker-ce-stable
docker-ce.x86_64 3:18.09.2-3.el7 docker-ce-stable
docker-ce.x86_64 3:18.09.1-3.el7 docker-ce-stable
docker-ce.x86_64 3:18.09.0-3.el7 docker-ce-stable
docker-ce.x86_64 18.06.3.ce-3.el7 docker-ce-stable
docker-ce.x86_64 18.06.2.ce-3.el7 docker-ce-stable
docker-ce.x86_64 18.06.1.ce-3.el7 docker-ce-stable
docker-ce.x86_64 18.06.0.ce-3.el7 docker-ce-stable
docker-ce.x86_64 18.03.1.ce-1.el7.centos docker-ce-stable
docker-ce.x86_64 18.03.0.ce-1.el7.centos docker-ce-stable
Kubernetes 1.15当前支持的docker版本列表是1.13.1, 17.03, 17.06, 17.09, 18.06, 18.09。 这里在各节点安装docker的18.09.7版本。
# yum makecache fast
# yum install -y --setopt=obsoletes=0 docker-ce
# systemctl start docker
# systemctl enable docker
安装指定版本docker
yum install -y –setopt=obsoletes=0 \ docker-ce-18.09.7-3.el7
确认一下iptables filter表中FOWARD链的默认策略(pllicy)为ACCEPT。
# iptables -nvL
Chain INPUT (policy ACCEPT 263 packets, 19209 bytes)
pkts bytes target prot opt in out source destination
Chain FORWARD (policy ACCEPT 0 packets, 0 bytes)
pkts bytes target prot opt in out source destination
0 0 DOCKER-USER all -- * * 0.0.0.0/0 0.0.0.0/0
0 0 DOCKER-ISOLATION-STAGE-1 all -- * * 0.0.0.0/0 0.0.0.0/0
0 0 ACCEPT all -- * docker0 0.0.0.0/0 0.0.0.0/0 ctstate RELATED,ESTABLISHED
0 0 DOCKER all -- * docker0 0.0.0.0/0 0.0.0.0/0
0 0 ACCEPT all -- docker0 !docker0 0.0.0.0/0 0.0.0.0/0
0 0 ACCEPT all -- docker0 docker0 0.0.0.0/0 0.0.0.0/0
2.4 修改docker cgroup driver为systemd
根据文档CRI installation中的内容，对于使用systemd作为init system的Linux的发行版，使用systemd作为docker的cgroup driver可以确保服务器节点在资源紧张的情况更加稳定，因此这里修改各个节点上docker的cgroup driver为systemd。
创建或修改/etc/docker/daemon.json：
{
"exec-opts": ["native.cgroupdriver=systemd"]
}
*如果机器是代理上网，需要配置docker的http代理:
# mkdir /etc/systemd/system/docker.service.d
# vim /etc/systemd/system/docker.service.d/http-proxy.conf
[Service]
Environment=”HTTP_PROXY=http://192.168.1.1:3128″
重启docker：
# systemctl daemon-reload
# systemctl restart docker
# docker info | grep Cgroup
Cgroup Driver: systemd
# systemctl show docker --property Environment
三、使用kubeadm部署Kubernetes
3.1 安装kubeadm和kubelet
Master配置
安装kubeadm和kubelet：
3.1.1、配置kubernetes.repo的源，由于官方源国内无法访问，这里使用阿里云yum源
cat <<EOF > /etc/yum.repos.d/kubernetes.repo
[kubernetes]
name=Kubernetes
baseurl=https://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64/
enabled=1
gpgcheck=1
repo_gpgcheck=1
gpgkey=https://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg https://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg
EOF
测试地址https://packages.cloud.google.com/yum/repos/kubernetes-el7-x86_64是否可用，如果不可用需要×××
# curl https://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64/
# yum -y makecache fast
# yum install -y kubelet kubeadm kubectl
...
Installed:
kubeadm.x86_64 0:1.15.0-0 kubectl.x86_64 0:1.15.0-0 kubelet.x86_64 0:1.15.0-0
Dependency Installed:
conntrack-tools.x86_64 0:1.4.4-4.el7 cri-tools.x86_64 0:1.12.0-0 kubernetes-cni.x86_64 0:0.7.5-0 libnetfilter_cthelper.x86_64 0:1.0.0-9.el7
libnetfilter_cttimeout.x86_64 0:1.0.0-6.el7 libnetfilter_queue.x86_64 0:1.0.2-2.el7_2
从安装结果可以看出还安装了cri-tools, kubernetes-cni, socat三个依赖：
•官方从Kubernetes 1.14开始将cni依赖升级到了0.7.5版本
•socat是kubelet的依赖
•cri-tools是CRI(Container Runtime Interface)容器运行时接口的命令行工具
运行kubelet –help可以看到原来kubelet的绝大多数命令行flag参数都被DEPRECATED了，如：
......
--address 0.0.0.0 The IP address for the Kubelet to serve on (set to 0.0.0.0 for all IPv4 interfaces and `::` for all IPv6 interfaces) (default 0.0.0.0) (DEPRECATED: This parameter should be set via the config file specified by the Kubelet's --config flag. See https://kubernetes.io/docs/tasks/administer-cluster/kubelet-config-file/ for more information.)
......
而官方推荐我们使用–config指定配置文件，并在配置文件中指定原来这些flag所配置的内容。具体内容可以查看这里Set Kubelet parameters via a config file。这也是Kubernetes为了支持动态Kubelet配置（Dynamic Kubelet Configuration）才这么做的，参考Reconfigure a Node’s Kubelet in a Live Cluster。
kubelet的配置文件必须是json或yaml格式，具体可查看这里。
Kubernetes 1.8开始要求关闭系统的Swap，如果不关闭，默认配置下kubelet将无法启动。 关闭系统的Swap方法如下:
# swapoff -a
修改 /etc/fstab 文件，注释掉 SWAP 的自动挂载，
# UUID=2d1e946c-f45d-4516-86cf-946bde9bdcd8 swap swap defaults 0 0
使用free -m确认swap已经关闭。 swappiness参数调整，修改/etc/sysctl.d/k8s.conf添加下面一行：
vm.swappiness=0
使修改生效
# sysctl -p /etc/sysctl.d/k8s.conf
3.2 使用kubeadm init初始化集群
开机启动kubelet服务：
systemctl enable kubelet.service
配置Master节点
# mkdir working && cd working
生成配置文件
# kubeadm config print init-defaults ClusterConfiguration > kubeadm.yaml
修改配置文件
# vim kubeadm.yaml
# 修改imageRepository：k8s.gcr.io
imageRepository: registry.aliyuncs.com/google_containers
# 修改KubernetesVersion:v1.15.0
kubernetesVersion: v1.15.0
# 配置MasterIP
advertiseAddress: 192.168.1.21
# 配置子网网络
networking:
dnsDomain: cluster.local
podSubnet: 10.244.0.0/16
serviceSubnet: 10.96.0.0/12
scheduler: {}
使用kubeadm默认配置初始化的集群，会在master节点打上node-role.kubernetes.io/master:NoSchedule的污点，阻止master节点接受调度运行工作负载。这里测试环境只有两个节点，所以将这个taint修改为node-role.kubernetes.io/master:PreferNoSchedule。
在开始初始化集群之前可以使用kubeadm config images pull预先在各个节点上拉取所k8s需要的docker镜像。
接下来使用kubeadm初始化集群，选择node1作为Master Node，在node1上执行下面的命令：
# kubeadm init --config kubeadm.yaml --ignore-preflight-errors=Swap
..........
Your Kubernetes control-plane has initialized successfully! To start using your cluster, you need to run the following as a regular user:
mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config
You should now deploy a pod network to the cluster. Run "kubectl apply -f [podnetwork].yaml" with one of the options listed at: https://kubernetes.io/docs/concepts/cluster-administration/addons/ Then you can join any number of worker nodes by running the following on each as root:
kubeadm join 192.168.1.21:6443 --token 4qcl2f.gtl3h8e5kjltuo0r \ --discovery-token-ca-cert-hash sha256:7ed5404175cc0bf18dbfe53f19d4a35b1e3d40c19b10924275868ebf2a3bbe6e
注意这一条命令需要保存好（添加集群使用）
kubeadm join 192.168.169.21:6443 –token 4qcl2f.gtl3h8e5kjltuo0r \ –discovery-token-ca-cert-hash sha256:7ed5404175cc0bf18dbfe53f19d4a35b1e3d40c19b10924275868ebf2a3bbe6e
上面记录了完成的初始化输出的内容，根据输出的内容基本上可以看出手动初始化安装一个Kubernetes集群所需要的关键步骤。 其中有以下关键内容：
[kubelet-start] 生成kubelet的配置文件”/var/lib/kubelet/config.yaml”
[certs]生成相关的各种证书
[kubeconfig]生成相关的kubeconfig文件
[control-plane]使用/etc/kubernetes/manifests目录中的yaml文件创建apiserver、controller-manager、scheduler的静态pod
[bootstraptoken]生成token记录下来，后边使用kubeadm join往集群中添加节点时会用到
下面的命令是配置常规用户如何使用kubectl访问集群：
mkdir -p $HOME/.kube
sudo cp -i /etc/kubernetes/admin.conf $HOME/.kube/config
sudo chown $(id -u):$(id -g) $HOME/.kube/config
最后给出了将节点加入集群的命令kubeadm join 192.168.169.21:6443 –token 4qcl2f.gtl3h8e5kjltuo0r \ –discovery-token-ca-cert-hash sha256:7ed5404175cc0bf18dbfe53f19d4a35b1e3d40c19b10924275868ebf2a3bbe6e
查看一下集群状态，确认个组件都处于healthy状态：
# kubectl get cs
NAME STATUS MESSAGE ERROR
controller-manager Healthy ok
scheduler Healthy ok
etcd-0 Healthy {"health":"true"}
集群初始化如果遇到问题，可以使用下面的命令进行清理：
# kubeadm reset
# ifconfig cni0 down
# ip link delete cni0
# ifconfig flannel.1 down
# ip link delete flannel.1
# rm -rf /var/lib/cni/
3.3 安装Pod Network
接下来安装flannel network add-on：
# mkdir -p ~/k8s/
# cd ~/k8s
# curl -O https://raw.githubusercontent.com/coreos/flannel/master/Documentation/kube-flannel.yml
# kubectl apply -f kube-flannel.yml
clusterrole.rbac.authorization.k8s.io/flannel created
clusterrolebinding.rbac.authorization.k8s.io/flannel created
serviceaccount/flannel created
configmap/kube-flannel-cfg created
daemonset.extensions/kube-flannel-ds-amd64 created
daemonset.extensions/kube-flannel-ds-arm64 created
daemonset.extensions/kube-flannel-ds-arm created
daemonset.extensions/kube-flannel-ds-ppc64le created
daemonset.extensions/kube-flannel-ds-s390x created
这里注意kube-flannel.yml这个文件里的flannel的镜像是0.11.0，quay.io/coreos/flannel:v0.11.0-amd64
如果Node有多个网卡的话，参考flannel issues 39701，目前需要在kube-flannel.yml中使用–iface参数指定集群主机内网网卡的名称，否则可能会出现dns无法解析。需要将kube-flannel.yml下载到本地，flanneld启动参数加上–iface=<iface-name>
containers:
- name: kube-flannel
image: quay.io/coreos/flannel:v0.11.0-amd64
command:
- /opt/bin/flanneld
args:
- --ip-masq
- --kube-subnet-mgr
- --iface=eth1
......
使用kubectl get pod –all-namespaces -o wide确保所有的Pod都处于Running状态。
# kubectl get pod -n kube-system
NAME READY STATUS RESTARTS AGE
coredns-5c98db65d4-dr8lf 1/1 Running 0 52m
coredns-5c98db65d4-lp8dg 1/1 Running 0 52m
etcd-node1 1/1 Running 0 51m
kube-apiserver-node1 1/1 Running 0 51m
kube-controller-manager-node1 1/1 Running 0 51m
kube-flannel-ds-amd64-mm296 1/1 Running 0 44s
kube-proxy-kchkf 1/1 Running 0 52m
kube-scheduler-node1 1/1 Running 0 51m
3.4 测试集群DNS是否可用
# kubectl run curl --image=radial/busyboxplus:curl -it
kubectl run --generator=deployment/apps.v1beta1 is DEPRECATED and will be removed in a future version. Use kubectl create instead.
If you don't see a command prompt, try pressing enter.
[ root@curl-5cc7b478b6-r997p:/ ]$
注：在此过程中可能会出现curl容器一直处于pending状态，报错信息如下：
0/1 nodes are available: 1 node(s) had taints that the pod didn’t tolerate.
解决方法：
# kubectl taint nodes –all node-role.kubernetes.io/master-
进入后执行nslookup kubernetes.default确认解析正常:
$ nslookup kubernetes.default
Server: 10.96.0.10
Address 1: 10.96.0.10 kube-dns.kube-system.svc.cluster.local
Name: kubernetes.default
Address 1: 10.96.0.1 kubernetes.default.svc.cluster.local
Node节点配置
安装docker的yum源:
# yum install -y yum-utils device-mapper-persistent-data lvm2
# yum-config-manager \
--add-repo \
https://download.docker.com/linux/centos/docker-ce.repo
# yum install -y --setopt=obsoletes=0 docker-ce
安装kubeadm和kubelet：
配置kubernetes.repo的源，由于官方源国内无法访问，这里使用阿里云yum源
cat <<EOF > /etc/yum.repos.d/kubernetes.repo
[kubernetes]
name=Kubernetes
baseurl=https://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64/
enabled=1
gpgcheck=1
repo_gpgcheck=1
gpgkey=https://mirrors.aliyun.com/kubernetes/yum/doc/yum-key.gpg https://mirrors.aliyun.com/kubernetes/yum/doc/rpm-package-key.gpg
EOF
测试地址https://packages.cloud.google.com/yum/repos/kubernetes-el7-x86_64是否可用，如果不可用需要×××
# curl https://mirrors.aliyun.com/kubernetes/yum/repos/kubernetes-el7-x86_64/
# yum -y makecache fast
# yum install -y kubelet kubeadm kubectl
...
Installed:
kubeadm.x86_64 0:1.15.0-0 kubectl.x86_64 0:1.15.0-0 kubelet.x86_64 0:1.15.0-0
Dependency Installed:
conntrack-tools.x86_64 0:1.4.4-4.el7 cri-tools.x86_64 0:1.12.0-0 kubernetes-cni.x86_64 0:0.7.5-0 libnetfilter_cthelper.x86_64 0:1.0.0-9.el7
libnetfilter_cttimeout.x86_64 0:1.0.0-6.el7 libnetfilter_queue.x86_64 0:1.0.2-2.el7_2
# swapoff -a
修改 /etc/fstab 文件，注释掉 SWAP 的自动挂载，
# UUID=2d1e946c-f45d-4516-86cf-946bde9bdcd8 swap swap defaults 0 0
使用free -m确认swap已经关闭。 swappiness参数调整，修改/etc/sysctl.d/k8s.conf添加下面一行：
net.bridge.bridge-nf-call-ip6tables = 1
net.bridge.bridge-nf-call-iptables = 1
net.ipv4.ip_forward = 1
vm.swappiness=0
使修改生效
# sysctl -p /etc/sysctl.d/k8s.conf
下面将node1这个主机添加到Kubernetes集群中，在node1上执行:
# kubeadm join 192.168.1.21:6443 --token 4qcl2f.gtl3h8e5kjltuo0r \
--discovery-token-ca-cert-hash sha256:7ed5404175cc0bf18dbfe53f19d4a35b1e3d40c19b10924275868ebf2a3bbe6e \
--ignore-preflight-errors=Swap
[preflight] Running pre-flight checks
[WARNING Swap]: running with swap on is not supported. Please disable swap
[WARNING Service-Kubelet]: kubelet service is not enabled, please run 'systemctl enable kubelet.service'
[preflight] Reading configuration from the cluster...
[preflight] FYI: You can look at this config file with 'kubectl -n kube-system get cm kubeadm-config -oyaml'
[kubelet-start] Downloading configuration for the kubelet from the "kubelet-config-1.15" ConfigMap in the kube-system namespace
[kubelet-start] Writing kubelet configuration to file "/var/lib/kubelet/config.yaml"
[kubelet-start] Writing kubelet environment file with flags to file "/var/lib/kubelet/kubeadm-flags.env"
[kubelet-start] Activating the kubelet service
[kubelet-start] Waiting for the kubelet to perform the TLS Bootstrap...
This node has joined the cluster:
* Certificate signing request was sent to apiserver and a response was received.
* The Kubelet was informed of the new secure connection details.
Run 'kubectl get nodes' on the control-plane to see this node join the cluster.
node1加入集群很是顺利，下面在master节点上执行命令查看集群中的节点：
# kubectl get node
NAME STATUS ROLES AGE VERSION
node1 Ready master 57m v1.15.0
node2 Ready <none> 11s v1.15.0
如何从集群中移除Node
如果需要从集群中移除node2这个Node执行下面的命令：
在master节点上执行：
# kubectl drain node2 –delete-local-data –force –ignore-daemonsets
# kubectl delete node node2
在node2上执行：
# kubeadm reset
# ifconfig cni0 down
# ip link delete cni0
# ifconfig flannel.1 down
# ip link delete flannel.1
# rm -rf /var/lib/cni/
报错：
error execution phase preflight: couldn’t validate the identity of the API Server: abort connecting to API servers after timeout of 5m0s
# kubeadm join ……
error execution phase preflight: couldn’t validate the identity of the API Server: abort connecting to API servers after timeout of 5m0
原因：master节点的token过期了
解决：重新生成新token
在master重新生成token
# kubeadm token create
424mp7.nkxx07p940mkl2nd
# openssl x509 -pubkey -in /etc/kubernetes/pki/ca.crt | openssl rsa -pubin -outform der 2>/dev/null | openssl dgst -sha256 -hex | sed ‘s/^.* //’
d88fb55cb1bd659023b11e61052b39bbfe99842b0636574a16c76df186fd5e0d
Node节点重新join就可以了
kubeadm join 192.168.169.21:6443 –token 424mp7.nkxx07p940mkl2nd \
--discovery-token-ca-cert-hash sha256:d88fb55cb1bd659023b11e61052b39bbfe99842b0636574a16c76df186fd5e0d
四、kube-proxy开启ipvs
修改ConfigMap的kube-system/kube-proxy中的config.conf，mode: “ipvs”
# kubectl edit cm kube-proxy -n kube-system
minSyncPeriod: 0s
scheduler: ""
syncPeriod: 30s
kind: KubeProxyConfiguration
metricsBindAddress: 127.0.0.1:10249
mode: "ipvs" # 加上这个
nodePortAddresses: null
其中mode原来是空，默认为iptables模式，改为ipvs
scheduler默认是空，默认负载均衡算法为轮训
编辑完，保存退出
删除所有kube-proxy的pod
# kubectl delete pod xxx -n kube-system
之后重启各个节点上的kube-proxy pod：
# kubectl get pod -n kube-system | grep kube-proxy | awk '{system("kubectl delete pod "$1" -n kube-system")}'
# kubectl get pod -n kube-system | grep kube-proxy
kube-proxy-7fsrg 1/1 Running 0 3s
kube-proxy-k8vhm 1/1 Running 0 9s
# kubectl logs kube-proxy-7fsrg -n kube-system
I0703 04:42:33.308289 1 server_others.go:170] Using ipvs Proxier.
W0703 04:42:33.309074 1 proxier.go:401] IPVS scheduler not specified, use rr by default
I0703 04:42:33.309831 1 server.go:534] Version: v1.15.0
I0703 04:42:33.320088 1 conntrack.go:52] Setting nf_conntrack_max to 131072
I0703 04:42:33.320365 1 config.go:96] Starting endpoints config controller
I0703 04:42:33.320393 1 controller_utils.go:1029] Waiting for caches to sync for endpoints config controller
I0703 04:42:33.320455 1 config.go:187] Starting service config controller
I0703 04:42:33.320470 1 controller_utils.go:1029] Waiting for caches to sync for service config controller
I0703 04:42:33.420899 1 controller_utils.go:1036] Caches are synced for endpoints config controller
I0703 04:42:33.420969 1 controller_utils.go:1036] Caches are synced for service config controller
日志中打印出了Using ipvs Proxier，说明ipvs模式已经开启。
五、Kubernetes常用组件部署
越来越多的公司和团队开始使用Helm这个Kubernetes的包管理器，这里也将使用Helm安装Kubernetes的常用组件。
5.1、Helm的安装
Helm由客户端命helm令行工具和服务端tiller组成，Helm的安装十分简单。 下载helm命令行工具到master节点node1的/usr/local/bin下，这里下载的2.14.1版本
# curl -O https://get.helm.sh/helm-v2.14.1-linux-amd64.tar.gz
# tar -zxvf helm-v2.14.1-linux-amd64.tar.gz
# cd linux-amd64/
# cp helm /usr/local/bin/
为了安装服务端tiller，还需要在这台机器上配置好kubectl工具和kubeconfig文件，确保kubectl工具可以在这台机器上访问apiserver且正常使用。 这里的node1节点已经配置好了kubectl。
因为Kubernetes APIServer开启了RBAC访问控制，所以需要创建tiller使用的service account: tiller并分配合适的角色给它。 详细内容可以查看helm文档中的Role-based Access Control。 这里简单起见直接分配cluster-admin这个集群内置的ClusterRole给它。创建helm-rbac.yaml文件
apiVersion: v1
kind: ServiceAccount
metadata:
name: tiller
namespace: kube-system
---
apiVersion: rbac.authorization.k8s.io/v1beta1
kind: ClusterRoleBinding
metadata:
name: tiller
roleRef:
apiGroup: rbac.authorization.k8s.io
kind: ClusterRole
name: cluster-admin
subjects:
- kind: ServiceAccount
name: tiller
namespace: kube-system
# kubectl create -f helm-rbac.yaml
serviceaccount/tiller created
clusterrolebinding.rbac.authorization.k8s.io/tiller created
接下来使用helm部署tiller:
# helm init --service-account tiller --skip-refresh
Creating /root/.helm
Creating /root/.helm/repository
Creating /root/.helm/repository/cache
Creating /root/.helm/repository/local
Creating /root/.helm/plugins
Creating /root/.helm/starters
Creating /root/.helm/cache/archive
Creating /root/.helm/repository/repositories.yaml
Adding stable repo with URL: https://kubernetes-charts.storage.googleapis.com
Adding local repo with URL: http://127.0.0.1:8879/charts
$HELM_HOME has been configured at /root/.helm.
Tiller (the Helm server-side component) has been installed into your Kubernetes Cluster.
Please note: by default, Tiller is deployed with an insecure 'allow unauthenticated users' policy.
To prevent this, run `helm init` with the --tiller-tls-verify flag.
For more information on securing your installation see: https://docs.helm.sh/using_helm/#securing-your-helm-installation
Happy Helming!
tiller默认被部署在k8s集群中的kube-system这个namespace下：
# kubectl get pod -n kube-system -l app=helm
NAME READY STATUS RESTARTS AGE
tiller-deploy-c4fd4cd68-dwkhv 1/1 Running 0 83s
注：如果tiller的状态一直是ErrImagePull的时候，需要更换国内helm源。
NAME READY STATUS RESTARTS AGE
tiller-deploy-7bf78cdbf7-fkx2z 0/1 ImagePullBackOff 0 79s
解决方法1：
1、删除默认源
# helm repo remove stable
2、 增加新的国内镜像源
# helm repo add stable https://burdenbear.github.io/kube-charts-mirror/
或
# helm repo add stable https://kubernetes.oss-cn-hangzhou.aliyuncs.com/charts
3、查看helm源情况
# helm repo list
4、搜索测试
# helm search mysql
解决方法2：
1、手动下载images
# docker pull registry.cn-hangzhou.aliyuncs.com/google_containers/tiller:v2.14.1
2、查看tiller需要的镜像名
# kubectl get pods -n kube-system
NAME READY STATUS RESTARTS AGE
coredns-bccdc95cf-tb6pf 1/1 Running 3 5h21m
coredns-bccdc95cf-xpgm8 1/1 Running 3 5h21m
etcd-master 1/1 Running 3 5h20m
kube-apiserver-master 1/1 Running 3 5h21m
kube-controller-manager-master 1/1 Running 3 5h21m
kube-flannel-ds-amd64-b4ksb 1/1 Running 3 5h18m
kube-flannel-ds-amd64-vmv29 1/1 Running 0 127m
kube-proxy-67zn6 1/1 Running 2 37m
kube-proxy-992ns 1/1 Running 0 37m
kube-scheduler-master 1/1 Running 3 5h21m
tiller-deploy-7bf78cdbf7-fkx2z 0/1 ImagePullBackOff 0 33m
3、使用describe查看镜像名
# kubectl describe pods tiller-deploy-7bf78cdbf7-fkx2z -n kube-system
……….
Normal Scheduled 32m default-scheduler Successfully assigned kube-system/tiller-deploy-7bf78cdbf7-fkx2z to node1
Normal Pulling 30m (x4 over 32m) kubelet, node1 Pulling image “gcr.io/kubernetes-helm/tiller:v2.14.1”
Warning Failed 30m (x4 over 31m) kubelet, node1 Failed to pull image “gcr.io/kubernetes-helm/tiller:v2.14.1”: rpc error: code = Unknown desc = Error response from daemon: Get https://gcr.io/v2/: Service Unavailable
Warning Failed 30m (x4 over 31m) kubelet, node1 Error: ErrImagePull
Warning Failed 30m (x6 over 31m) kubelet, node1 Error: ImagePullBackOff
Normal BackOff 111s (x129 over 31m) kubelet, node1 Back-off pulling image “gcr.io/kubernetes-helm/tiller:v2.14.1”
4、使用docker tag 重命令镜像
# docker tag registry.cn-hangzhou.aliyuncs.com/google_containers/tiller:v2.14.1 gcr.io/kubernetes-helm/tiller:v2.14.1
5、删除多余的镜像
# docker rmi registry.cn-hangzhou.aliyuncs.com/google_containers/tiller:v2.14.1
6、删除失败的pod
# kubectl delete deployment tiller-deploy -n kube-system
稍等一会儿就可以使用kubectl get pods -n kube-system查看状态已经正常了
# helm version
Client: &version.Version{SemVer:"v2.14.1", GitCommit:"5270352a09c7e8b6e8c9593002a73535276507c0", GitTreeState:"clean"}
Server: &version.Version{SemVer:"v2.14.1", GitCommit:"5270352a09c7e8b6e8c9593002a73535276507c0", GitTreeState:"clean"}
注意由于某些原因需要网络可以访问gcr.io和kubernetes-charts.storage.googleapis.com，如果无法访问可以通过helm init –service-account tiller –tiller-image <your-docker-registry>/tiller:v2.13.1 –skip-refresh使用私有镜像仓库中的tiller镜像
最后在node1上修改helm chart仓库的地址为azure提供的镜像地址：
# helm repo add stable http://mirror.azure.cn/kubernetes/charts
"stable" has been added to your repositories
# helm repo list
NAME URL
stable http://mirror.azure.cn/kubernetes/charts
local http://127.0.0.1:8879/charts
5.2、使用Helm部署Nginx Ingress
为了便于将集群中的服务暴露到集群外部，需要使用Ingress。接下来使用Helm将Nginx Ingress部署到Kubernetes上。 Nginx Ingress Controller被部署在Kubernetes的边缘节点上，关于Kubernetes边缘节点的高可用相关的内容可以查看之前整理的Bare metal环境下Kubernetes Ingress边缘节点的高可用,Ingress Controller使用hostNetwork。
我们将master(192.168.1.21)做为边缘节点，打上Label：
# kubectl label node master node-role.kubernetes.io/edge=
node/master labeled
# kubectl get node
NAME STATUS ROLES AGE VERSION
master Ready edge,master 138m v1.15.0
node1 Ready <none> 82m v1.15.0
如果想删除一个node的label标记，使用以下命令
# kubectl label node node1 node-role.kubernetes.io/edge-
创建 ingress-nginx.yaml
stable/nginx-ingress chart的值文件ingress-nginx.yaml如下：
controller:
replicaCount: 1
hostNetwork: true
nodeSelector:
node-role.kubernetes.io/edge: ''
affinity:
podAntiAffinity:
requiredDuringSchedulingIgnoredDuringExecution:
- labelSelector:
matchExpressions:
- key: app
operator: In
values:
- nginx-ingress
- key: component
operator: In
values:
- controller
topologyKey: kubernetes.io/hostname
tolerations:
- key: node-role.kubernetes.io/master
operator: Exists
effect: NoSchedule
- key: node-role.kubernetes.io/master
operator: Exists
effect: PreferNoSchedule
defaultBackend:
nodeSelector:
node-role.kubernetes.io/edge: ''
tolerations:
- key: node-role.kubernetes.io/master
operator: Exists
effect: NoSchedule
- key: node-role.kubernetes.io/master
operator: Exists
effect: PreferNoSchedule
nginx ingress controller的副本数replicaCount为1，将被调度到master这个边缘节点上。这里并没有指定nginx ingress controller service的externalIPs，而是通过hostNetwork: true设置nginx ingress controller使用宿主机网络。
# helm repo update
# helm install stable/nginx-ingress \
-n nginx-ingress \
--namespace ingress-nginx \
-f ingress-nginx.yaml
# kubectl get pod -n ingress-nginx -o wide
NAME READY STATUS RESTARTS AGE IP NODE NOMINATED NODE READINESS GATES
nginx-ingress-controller-cc9b6d55b-pr8vr 1/1 Running 0 10m 192.168.1.21 node1 <none> <none>
nginx-ingress-default-backend-cc888fd56-bf4h2 1/1 Running 0 10m 10.244.0.14 node1 <none> <none>
如果发现nginx-ingress的容器状态是ContainersCreating/ImagePullBackOff，则需要手动下载镜像
# docker pull registry.aliyuncs.com/google_containers/nginx-ingress-controller:0.25.0
# docker tag registry.aliyuncs.com/google_containers/nginx-ingress-controller:0.25.0 quay.io/kubernetes-ingress-controller/nginx-ingress-controller:0.25.0
# docker pull registry.cn-qingdao.aliyuncs.com/kubernetes_xingej/defaultbackend-amd64:1.5
# docker tag registry.cn-qingdao.aliyuncs.com/kubernetes_xingej/defaultbackend-amd64:1.5 k8s.gcr.io/defaultbackend-amd64:1.5
# docker rmi registry.cn-qingdao.aliyuncs.com/kubernetes_xingej/defaultbackend-amd64:1.5
# docker rim registry.aliyuncs.com/google_containers/nginx-ingress-controller:0.25.0
如果访问http://192.168.1.21返回default backend，则部署完成。
5.3、 使用Helm部署dashboard
创建 kubernetes-dashboard.yaml：
image:
repository: registry.aliyuncs.com/google_containers/kubernetes-dashboard-amd64
tag: v1.10.1
ingress:
enabled: true
hosts:
- k8s.frognew.com #这里是你将来访问dashboard的域名
annotations:
nginx.ingress.kubernetes.io/ssl-redirect: "true"
nginx.ingress.kubernetes.io/backend-protocol: "HTTPS"
tls:
- secretName: frognew-com-tls-secret
hosts:
- k8s.frognew.com
nodeSelector:
node-role.kubernetes.io/edge: ''
tolerations:
- key: node-role.kubernetes.io/master
operator: Exists
effect: NoSchedule
- key: node-role.kubernetes.io/master
operator: Exists
effect: PreferNoSchedule
rbac:
clusterAdminRole: true
执行安装
helm install stable/kubernetes-dashboard \
-n kubernetes-dashboard \
--namespace kube-system \
-f kubernetes-dashboard.yaml
5.4、生成用户token
a、创建admin-sa.yaml
apiVersion: rbac.authorization.k8s.io/v1beta1
metadata:
name: admin
annotations:
rbac.authorization.kubernetes.io/autoupdate: "true"
roleRef:
kind: ClusterRole
name: cluster-admin
apiGroup: rbac.authorization.k8s.io
subjects:
kind: ServiceAccount
name: admin
namespace: kube-system
apiVersion: v1
kind: ServiceAccount
metadata:
name: admin
namespace: kube-system
labels:
kubernetes.io/cluster-service: "true"
addonmanager.kubernetes.io/mode: Reconcile
b、创建admin-sa的pod
# kubectl create -f admin-sa.yaml
# kubectl get secret -n kube-system
NAME TYPE DATA AGE
admin-token-2tbzp kubernetes.io/service-account-token 3 9m5s
attachdetach-controller-token-bmz2c kubernetes.io/service-account-token 3 27h
bootstrap-signer-token-6jctj kubernetes.io/service-account-token 3 27h
certificate-controller-token-l4l9c kubernetes.io/service-account-token 3 27h
c、生成 admin-token
# kubectl get secret admin-token-2tbzp -o jsonpath={.data.token} -n kube-system|base64 -d
eyJhbGciOiJSUzI1NiIsImtpZCI6IiJ9.eyJpc3MiOiJrdWJlcm5ldGVzL3NlcnZpY2VhY2NvdW50Iiwia3ViZXJuZXRlcy5pby9zZXJ2aWNlYWNjb3VudC9uYW1lc3BhY2UiOiJrdWJlLXN5c3RlbSIsImt1YmVybmV0ZXMuaW8vc2VydmljZWFjY291bnQvc2VjcmV0Lm5hbWUiOiJhZG1pbi10b2tlbi0ydGJ6cCIsImt1YmVybmV0ZXMuaW8vc2VydmljZWFjY291bnQvc2VydmljZS1hY2NvdW50Lm5hbWUiOiJhZG1pbiIsImt1YmVybmV0ZXMuaW8vc2VydmljZWFjY291bnQvc2VydmljZS1hY2NvdW50LnVpZCI6ImRlOGU5N2EzLWY1YmItNGRlNC1hN2Q1LTY5YzEwYTIyZTE3OSIsInN1YiI6InN5c3RlbTpzZXJ2aWNlYWNjb3VudDprdWJlLXN5c3RlbTphZG1pbiJ9.NgZvr3XTtrW1XPCJHYRFFdPD1IfsoRRTYJHwAST2gfhY1hva_yIoh1ATSpDO551rNio0ulb7YllSiZMaQViBeFTiAhuuIlKHKyELOoB_eY7jFTCVstdr4vQzH5e2GRQgljEeqbF9Lewr0n_eqIS6pgVQSRT8at-Yk6EXLM0XhYf4qbAvMuztuRTSp8JKmal65gwTxTJU7LpjJM7UbZ8UelVOjNZK8BFCezGv0ccqXywLu5-aAj2NvSHVThg6jybj37R0hszqRw2fkGZtIcEOEtgmij2vHa3oNb3f38gd1eE6WqZpJpVOPLlX6QNSxiV0jaaj9AqodFCdAg48E75Bvg
注意：admin-token的pod名称
其中 admin-token-2tbzp 是 kubectl get secret -n kube-system 看到的admin-token名称
d、使用生成的token去浏览器中登录
